Method and apparatus for making gussetted package

ABSTRACT

Methods and apparatus for making gussetted packages having openable and reclosable interlocking seals, the seals having male and female portions, snap detents, and formed transversely to the direction of film flow. The packaging film is provided at package length intervals with thermoformable strips secured thereto transversely to the running length of the film, and is fed to a modified standard vertical form, fill and seal packaging machine with gussets forming tooling where the film is formed into a bag with the thermoformable strips inside at the upper end of the bag, product deposited into the bag, the bag sealed, the reclosable interlocking seal formed, and the bag severed from the next bag being formed. The reclosable seal provides auditory and tactile indications of seal closing. Some packages are formed with the thermoformable strips in the gusset, and some are formed with the gusset free of strip material.

[0001] This application is a continuation in part of copendingapplication Ser. No. 09/693,963 filed on Oct. 23, 2001, and is acontinuation of copending application Ser. No. 09/850,085 filed on May8, 2001.

[0002] This invention relates generally to packaging systems, and moreparticularly to flexible gussetted packages having an openable andreclosable interlocking seal provided with snap detents spaced along amajor part of the length of the seal, the reclosable interlocking sealhaving male and female parts with the detents being formed in the femalepart and extending into the male part. The novel seal and snap detentsstructure provides tactile and auditory snap indications of the state ofthe seal during opening and closing of the package. Disclosed aremethods and apparatus for making such packages and seals from acontinuous web of flexible film, the seals being formed during packageformation at line speed.

BACKGROUND OF THE INVENTION

[0003] The advantages of gussetted packages for the storage of somekinds of substances is well known, and particularly where a wide mouthpackage or pour spout is desired. They also provide superior casepacking and display shelf utilization as compared to stand-up poucheswhich may have zipper closures. The known art directed toward gussettedpackages with some form of snap closure is Galomb U. S. Pat. No.6,082,897. Galomb discloses a bulky two element semi-rigid snapstructure comprising a male part and a female part both affixed to theoutside of the package by tacking or adhesive, each of which parts issecured to the package material along only one of the part edges so thatthe package material can move longitudinally relatively to the femalepart and can be stuffed into it by the male part during package closure.The snap parts are sufficiently bulky and rigid that they are notcapable of being run over the forming collar of a vertical form fillapparatus and must be separately inventoried and affixed to the packageafter it has been formed. No apparatus for or method of making thepackage is disclosed by Galomb.

SUMMARY OF THE INVENTION

[0004] The method and apparatus for making the gussetted packageaccording to the present invention utilize composite packaging filmstructures comprising the packaging film with several differentconfigurations of strips of formable plastic laminated to the film atpackage length intervals from which several different gussetted packagesare respectively formed, some packages having the formable plastic stripwithin the gussets and some packages which utilize relatively thickpackaging film having the gussets formed without such plastic strip. Thecomposite packaging film structures may be preformed and stored as rollstock material, which does not appear to be practical with the Galombstructure, or may be concurrently made with package formation by a SigPack, Inc. Easy Snap™ Laminator mounted atop or adjacent to thepackaging apparatus to form one of the shown and to be describedspecific novel composite packaging film structures, which composite filmis then fed into the packaging apparatus with the plastic stripsdisposed on the inside of the package and incorporated into the novelreclosable seal formed in the film and strip composite. The laminatorfunctions with both horizontal and vertical form/fill/seal wrappingmachines and with overwrap packagers, and laminates various plasticstrip materials to diverse heat seal packaging films to selectively formseveral related types of gussetted packages.

[0005] As disclosed in copending application Ser. No. 091693,963, thepackaging films could be for example, polypropylene, polyethylene,polystyrene, polyvinylchloride, thermoplastic heat seal coatednon-plastic films, and various film laminations of two to four layers,while the plastic strip could be formed of one to three layers. In someapplications the strip could be a single thickness of polyvinylchloride(PVC) heat sealed to a PVC film at a temperature of about 230° F. for ½to ¾ seconds, while in other applications the strip could be of twolayers such as PVC plus a sealing layer, or three layers such as acenter layer coated on opposite sides respectively with a sealing layerand a release layer to prevent the strip from self adhering duringformation of the reclosable interlock seal. A commonly used packagingfilm is a four layer film consisting of two layers of polypropyleneseparated by a layer of low density polyethylene and having a heat seallayer of low density polyethylene coated on one face.

[0006] The invention is shown and described in conjunction with amodified vertical form, fill and seal packaging machine having a novelpackage sealing press which latter also forms the novel resealableclosure, the packaging machine being for example a Sig Pack, Inc. EagleInfinity, Model 1524 fitted with standard gusset tooling,

[0007] Gussetted packages made according to the invention incorporatingthe novel reclosable seal also address consumer complaints relating toprior art zipper seals by providing clear auditory and tactileindications of the closing of the reclosable seal by incorporation ofsnap detents, so that the consumer is assured that the package has beenresealed even in the absence of visual package inspection.

[0008] Accordingly, it is a primary object of the invention to providenovel methods and apparatus for making gussetted packages with openableand reclosable interlocking seals.

[0009] An additional object of the invention is to provide novel methodsand apparatus for making gussetted packages having a novel openable andreclosable interlocking seal as aforesaid in which the bulk of the sealstructure is provided by an added layer of strip material secured in aspecific way to the packaging film at package length intervals.

[0010] A further object of the invention is to provide novel methods andapparatus for making gussetted packages having novel openable andreclosable interlocking seals as aforesaid in which the ends of thestrip material are positioned in abutment at substantially the center ofone face of the package to provide a hinge to assist in package opening.

[0011] Still another object of the invention is to provide novel methodsand apparatus for making gussetted packages having reclosableinterlocking package seals having male and female parts with snapdetents formed in the parts, the closure structure providing tactile andauditory snap indications of the state of the closure during opening andclosing of the package.

[0012] A yet further object of the invention is to provide novel methodsand apparatus for making gussetted packages as aforesaid in which thereclosable interlocking seal is formed from the packaging film and aheat sealable strip heat sealed to the packaging film.

[0013] A still further object of the invention is to provide novelmethods and apparatus for making gussetted packages as aforesaid inwhich the packages may be formed from a variety of packaging films suchas polypropylene, polyethelene, polystyrene, polyvinylchloride, andvarious film laminates.

[0014] The foregoing and other objects of the invention will be moreclearly understood from a reading of the following description inconjunction with an examination of the appended drawings, wherein:

[0015]FIG. 1 is a diagrammatic side view of the apparatus according tothe invention showing the method and stages of gussetted packageforming, filling, sealing, and severing;

[0016]FIG. 2 is a diagrammatic front view of the apparatus seen in FIG.1;

[0017]FIG. 2A is an isometric view of the gusset tooling utilized in theapparatus of FIGS. 1 and 2;

[0018]FIG. 3 is a plan view of a portion of one form of the compositefilm showing the packaging film and the placement of the attachedplastic strips suitable for making a gussetted package having a fin seallongitudinal seal, and in which the gussets include a portion of theplastic strip material;

[0019]FIG. 4 is a diagrammatic cross section view through an open topgussetted package formed from the film of FIG. 3 showing the sidesgussets which include a portion of the plastic strip material;

[0020]FIG. 4A is a diagrammatic cross sectional view of the package ofFIG. 4 in its closed condition;

[0021]FIG. 5 is a plan view of a portion of another form of thecomposite film showing the packaging film and the placement of theattached strip suitable for making a gussetted package in which bothside gussets are free of the plastic strip material and are formed onlyby the packaging film;

[0022]FIG. 6 is a diagrammatic cross section view through an opengussetted package formed from the film of FIG. 5;

[0023]FIG. 6A is a diagrammatic cross sectional view of the package ofFIG. 6 in its closed condition;

[0024]FIG. 7 is a plan view of a portion of another form of thecomposite film showing the packaging film and the placement of anattached plastic strip suitable for making a gussetted package having afin seal longitudinal seal, a half package transversely extending fixedseal, and a half package transversely extending gussetted reclosableseal;

[0025]FIG. 8 is a diagrammatic cross section view through an openreclosable seal gussetted package formed from the film of FIG. 7, thepackage having a fin seal longitudinal seal, a half package transverselyextending fixed seal, and a half package transversely extendinggussetted reclosable seal in which the gusset include a portion of theplastic strip material;

[0026]FIG. 8A is a diagrammatic cross sectional view of the package ofFIG. 8 in its closed condition;

[0027]FIG. 9 is a plan view of a portion of yet another form ofcomposite film showing the packaging film and the placement of theattached plastic strips suitable for making a gussetted package having afin seal longitudinal seal, a half package transversely extending fixedseal, and a half package transversely extending gussetted reclosableseal, and in which the gussets are free of any plastic strip material;

[0028]FIG. 10 is a diagrammatic cross section view through an openreclosable seal gussetted package formed from the film of FIG. 9;

[0029]FIG. 10A is a diagrammatic cross sectional view of the package ofFIG. 10 in its closed condition;

[0030]FIG. 11 is an enlarged expanded vertical cross sectional viewshowing the detailed structure of the gussetting tooling and sealsforming and package severing apparatus shown in the phantom circle 11 onFIG. 1;

[0031]FIGS. 11A through 11C show successive steps in the ends sealing,reclosable seal forming, and package severing process;

[0032]FIG. 12 is an isometric view showing the forming dies which formthe snap detents in the reclosable interlocking seal, with a part of thereclosable seal shown in phantom outline;

[0033]FIG. 13 is an enlarged fragmentary isometric view of the inner andouter parts of the reclosable seal in separated position, showing thesnap detents in the sidewalls of the seal adjacent to the arrowheadinterlock;

[0034]FIG. 14 is an enlarged cross section through the reclosable sealshown in the phantom circle on FIG. 11C showing the placement of theforming dies of FIG. 12 and between the snap detents;

[0035]FIG. 15 is an enlarged cross section through the reclosable sealand the snap detents which are formed between the teeth of the formingdies, as would be seen when viewed along line 15—15 on FIG. 12;

[0036]FIG. 16 is an isometric view of a gussetted package made accordingto the invention of the type shown in FIG. 6 but showing alongitudinally extending overlap package seal uppermost, the package endseals, the integrally formed reclosable seal with the female portionuppermost and the seal detent snaps;

[0037]FIG. 17 shows the package of FIG. 16 with the top end seal removedand the package opened;

[0038]FIG. 18 is a showing similar to that of FIG. 17 but for thepackage of FIG. 10;

[0039]FIG. 19 is is an enlarged cross sectional diagrammatic showing ofthe upper end of a package including the novel reclosable interlockingseal made according to the invention in its closed condition, and thepackage top heat seal spaced above the reclosable seal with anintervening length of unsecured package film; and

[0040]FIG. 20 is an enlarged cross sectional diagrammatic showing of thenovel reclosable interlocking seal made according to the inventionsimilar to FIG. 19 but with the reclosable seal partly pulled open fromthe top;

[0041] In the several figures, like elements are denoted by likereference characters, and to the extent possible the referencecharacters are consistent with those of copending application Ser. No.09/693,963.

[0042] Considering first the side and front diagrammatic elevationalviews of FIGS. 1 and 2, there is seen a modified conventional verticalform-fill packaging apparatus designated generally as 20 for forminggussetted packages, and which could be for example a Sig Pack, Inc.Eagle Infinity, Model 1524, comprising a vertical cylindrical fill tube21 surmounted by a conical feed horn 22 into which the material to bepackaged is deposited. Disposed adjacent to the feed horn 22 at an angleof about fifteen degrees above the horizontal and turned downward aroundthe feed horn 22 and fill tube 21 with a slight space therebetween is afill tube forming collar 23, the purpose of which, together with thefill tube 21, is to form a composite web of packaging material 24 beingfed over the forming collar 23 into a tube having a longitudinallyextending seal 26 formed by the heat seal device 27.

[0043] A pair of belt drives 28, by pulling downward on the tube 25,pull the web 24 downward off of the supply roll 29 or from the compositeweb forming apparatus 30 which laminates thermoformable strips 31 to thepackaging material 32 to form the composite web of packaging material24. The apparatus 30 may be a a Sig Pack, Inc. Easy Snap™ Laminator. Thefilled descending tube is formed into a gussetted tube 25 by the gussettooling, designated generally at 50 and described more fully inconnection with FIGS. 2 and 2A, the gussetted tube passing through thebottom press 33 where it pauses for formation of the top seal 35, thereclosable seal 36, formation of a bottom seal 37 of the next descendingpackage, and severing of the completed package 34 from the above lyingtube. The completed package 34 is carried away by the conveyor 38.

[0044] The apparatus of FIGS. 1 and 2 departs from conventional verticalform-fill apparatus in several particulars, first, by modifying theorientation of the fill tube forming collar 23 to the surface of theconical feed horn 22 by reorienting the forming collar as shown anddescribed in copending application Ser. No. 09/693,963, and providing aleading edge tack 44 to the strips 31, as shown in FIGS. 3, 5, 7, and 9to be subsequently described. The second difference is the inclusion ofthe subsequently to be described novel bottom press 33 which forms thenovel gussetted reclosable seal, in conjunction with the gussettingtooling 50. The gusset forming tooling 50 is seen in FIGS. 1 and 2positioned with the gusset forming plow 51 positioned above the press 33and with the gusset maintaining tool 52 positioned below the press 33 sothat the shape of the gussetted tube 25 is formed above and maintainedthroughout and somewhat below the vertical extent of the press 33,whereby the press acts on the gussettted form of the tube 25. Details ofthe gusset forming tooling 50, including the upper plow 51 and the lowermaintainer 52 are best seen in the showing of FIG. 2A which also showsthe reciprocating mechanism for retracting and inserting the gussetforming plow 51 and maintainer 52.

[0045] Considering now FIGS. 3, 5, 7, and 9, there are seen thepackaging film material 32 and respectively a plurality of differentconfigurations of thermoformable strips 31, 131A and 131B,231, and 331Aand 331B, secured to the film 32 substantially continuously along thestrips trailing edges 39 by heat seals 40, along the strips ends 41 asat 42, and by short tacks 43 at the center of the strips leading edges44 to insure that the leading edge is against the packaging film as thecomposite web passes into the space between the feed horn 22 and formingcollar 23 to prevent tearing off the strips from the film. The stripsare all secured to the film inward from the film side edges to providethe margins 48 for formation of the longitudinal fin seals 26. Varioustypes of suitable plastic strip material are shown and described incopending application Ser. No. 09/693,963.

[0046]FIGS. 3, 5, 7, and 9 show the different configurations of stripson the film 32, required to form the different gussetted packages ofFIGS. 4, 6, 8, and 10 respectively. Strip 31 of FIG. 3 produces thegussetted package of FIG. 4 having the strip 31 extending completelyperipherally around the inside of the gussetted tube, in the sides ofthe package and in the gussets 55. Strips 131A and 131B of FIG. 5 formthe gussetted package of FIG. 6 with both gussets free of the plasticstrip material and formed only by the packaging film 32, the gussetsbeing defined by the film regions 53 shown in FIGS. 5, 6, 9, and 10.Strip 231 of FIG. 7 forms the gussetted package of FIG. 8 having a finseal longitudinal seal, a half package transversely extending fixed seal54, and a half package transversely extending gussetted reclosable sealin which the gusset 55 includes a portion of the plastic strip material231. Strips 331A and 331B of FIG. 9 form the gussetted package of FIG.10 having a fin seal longitudinal seal, a half package transverselyextending fixed seal 54′ like that of 54 in FIG. 8, and a half packagetransversely extending gussetted reclosable seal in which the gusset isfree of the plastic strip material and formed only by the packaging film32, the gusset being defined by the film region 53 also shown in FIG. 9.The package transverse extents of the fixed seals 54 of FIGS. 8,8A, 10,and 10A relative to the extents of the package reclosable seals has beenshown as substantially equal, but other ratios can be chosen as desired.

[0047] The strips 31 and 131A are also provided with apertures 49through the strips which in the completed packages act as a weakenedregion allowing a hinge fold to occur when the package is opened.Another hinge is provided in the completed packages opposite the firsthinge by the substantially abutting apposed ends 41 of the strips 31,131B, 231, and 331A and 331B as seen in FIGS. 4, 6, 8, and 10, all ofwhich show a fin seal longitudinal package seal 26 formed by the sidemargins 48. An overlap longitudinal seal may be made by other verticalform-fill machines, and such is illustrated in FIG. 13.

[0048] Turning now to FIGS. 11 through 11C which illustrate theformation of the package end seals and reclosable seal of the package ofFIG. 4, there is seen in FIG. 11 a partly completed gussetted package 34which has been filled with product 56 while descending, and has stoppedat a position where the upper part of the package is within the bottompress 33 just prior to completion by the formation of the top seal andreclosable seal. The package 34 is stopped so that the thermoformablestrip 31 is positioned between the reclosable seal forming horizontallyreciprocable heated female die 58 and the two part heated male die 57,with an above-lying length 59 of the tube 25 positioned below thecomposite heated dies 60 and 61 and the package severing cutter 62 andanvil 63. The female die 58 is provided with a forming recess 68, andthe male die is provided with a forming wedge 69 carried by the male diepart 57B and shaped complementally to the female die recess 68. Thecomposite dies 60 and 61 consist of a pair of dies 64 which form the topseal 35 of the package 34 being completed, and a pair of above-lyingdies 65 which form the bottom seal 37 of the next package to descend.Disposed above and below the forming recess 68 of female die 58 are apair of heated reclosable seal detent forming toothed dies 66reciprocable with the female die 58 and pivotable toward one another onpivots 67.

[0049]FIG. 11A shows the reclosable seal forming heated dies 57 and 58moved toward one another and into engagement, heat forming the packagefilm 32 and thermoformable strip 31 into the recess of the female die 58to form the point of the arrowhead shaped reclosable seal. For clarity,the strip 31 is not shown in FIGS. 11A through 11C, but its location isseen clearly from FIGS. 11 and 13 to 15. At the same time, the heateddies 60 and 61 heat seal the gussetted tube 25 entirely widthwise for avertical interval 70 and define the unsecured interval 59 between thebottom of the top seal 35 and the top of the reclosable seal 36, theportion of the seal 70 heated by the dies 64 becoming the package topseal 35, and the portion of the seal 70 heated by the dies 65 becomingthe bottom seal 37 of the next descending package when the seal 70 issubsequently severed widthwise by the cutter 62.

[0050] The next step is a hybrid between FIGS. 11A and 11B in which theconditions are as shown in FIG. 11A except that the detent forming dies66 have pivoted inward and closed sufficiently to begin formation of theinwardly sloping bottom surfaces 72 of the arrowhead shaped interlock,but not sufficiently to clamp the male die forming wedge 69.

[0051]FIG. 11B shows the immediately following condition in which thecutter 62 has moved laterally to sever the heat seal 70 against theanvil 63 and separate the package 34 from the above-lying tube 25. Atthe same time, male die part 57B carrying the wedge 69 partiallyretracts from the recess 68 of female die 58 and from between the teeth71 of the dies 66, and the dies 66 pivot further inward driving thedetent forming die teeth 71 toward one another to their maximum closedposition, the teeth 71 pinching the packaging film 32 and thermoformablestrip 31 therebetween to form the film and strip into the female dierecess to continue forming the inwardly sloping bottom surfaces 72 ofthe arrowhead shaped reclosable seal 36, and forming the snap detents 73best seen in FIGS. 11 and 13. The female die 58 is then moved somewhatleft toward the dies 66 to set the arrowhead shape between itself andthe facing surfaces of teeth 71 of detent forming dies 66. The detents73 are formed because as the softened thermoformable material of thefilm and strip are compressed between the teeth 71 the only directionthat the compressed material can move is laterally into the spacesbetween the teeth 71, and then bulge outward between the teeth, formingthe detents 73.

[0052]FIG. 11C shows the male and female dies 57 and 58 outwardlyretracted with the female die laterally carrying the package 34 heldwithin it by the unopened detent forming dies 66, and the package endseal dies 60 and 61 and the cutter 62 have been retracted. The dies 66remain engaged for a short time to complete setting of the detents,after which they open and release the completed package which drops tothe conveyor 38 as shown in FIG. 1, and the sequence commencing withFIG. 11 is repeated. Sequencing and timing controls and drives for thesequential movements of the various dies is provided by standardcommercially available components.

[0053]FIGS. 12 through 15 show in greater detail the detent formingtoothed dies 66 and the structure of the reclosable seal 36. FIG. 12shows more clearly the relationship between the dies and the reclosableseal, and shows the shorter die teeth 76 on one side of the die in thecentral region of the die corresponding to the region of the overlaplongitudinal package seal 26 formed by the film margin 47, as best shownin FIG. 13, and also for a fin seal as shown in the earlier figures. Thedies 66 are also formed at their opposite apposed ends with long flatteeth 80 which are slightly lower than the teeth 71 to accommodate theextra thickness of material in the gussets, the difference in elevationof the teeth 71 and 80 being on the order of thousandths of an inch. Insome cases it has also been found desirable to slightly taper the teeth80 downward from their beginning adjacent to the teeth 71 toward the dieends.

[0054]FIG. 13 also shows more clearly the snap detents 73 which areformed in the seal male part 36A and female part 36B by an outwardbulging of the thermoformable material between adjacent teeth 71 of thedies 66 when the dies close. The heat softened material between theapposed die teeth is compressed and can only move laterally, but suchmovement causes the outward bulging of the material which forms thedetents since material is moving from opposite sides into the same spacebetween the adjacent die teeth and can not move inward. This is alsoshown in FIG. 14 in which the detents 73 are shown behind the die teeth71. FIG. 15 is a section taken through the detents and shows theinterfitted arrangement.

[0055]FIG. 16 shows a completed gussetted package of the type shown inFIG. 6 about to be opened by cutting off the top heat seal 35 withscissors 77, and FIG. 17 shows the package of FIG. 16 with the top heatseal removed and pulled open, the bag remaining open because of thegussets and hinging folds 78 and 79. The hinge 78 results from theweakening produced by the strip 31 aperture 49 which is formed into therelatively rigid male part 36A of the reclosable seal 36, while thehinge 79 is formed at the abutment of the ends of the strip 31 locatedin the female part 36B. The package is simply closed by inward directedfinger pressure on the outside of the package along the male and femaleparts 36A and 36B of reclosable seal 36 which causes the package sidesto infold the gussets and snap to each other so that the snap detentsinterlock. FIG. 18 is a showing similar to that of FIG. 17, but for apackage of the type shown in FIG. 10, illustrating the pour spoutconfiguration achieved with this form of package.

[0056]FIGS. 19 and 20 show the upper end of a package 34 in enlargeddiagrammatic cross section to illustrate the opening of the package. Asshown in FIG. 19, the top seal is removed by cutting below it to providethe free top tabs of packaging film 32 shown in FIG. 20. These top tabsare pulled away from each other as shown in FIG. 20 to open the femalepart 36B of the reclosable seal and disengage it from the inner malepart 36A. The opening leverage is materially increased because the strip31 is sealed to the film 32 by the trailing edge heat seal 40 and theopening pull is transmitted through the strip 31. Conversely,inadvertent opening of the package from the body side of the package isdiscriminated against because the strip 31 is substantially unsecured tothe package film 32 at its leading edge 44 inside the package and thereis no reinforcement of pull on the film by the strip.

[0057] Having now described the invention in connection withparticularly illustrated embodiments thereof, it will be understood thatmodifications and variations of the invention may now occur from time totime to those normally skilled in the art without departing from theessential scope or spirit of the invention, and accordingly it isintended to claim the invention both broadly and specifically asindicated in the appended claims.

What is claimed is:
 32. A method of making a flexible gussetted packageformed from a continuous web of substantially constant thicknesspackaging material characterized by having front and rear faces and atleast one gussetted side extending between said front and rear faces, arepeatably openable and reclosable interlocking seal operative to openand close said package body to provide and prevent respectively accessto the package interior, said reclosable interlocking seal extendingthrough said front and rear faces and at least one gussetted side ofsaid package and comprising in combination, inner and outer interlockingportions, the inner and outer portions of said seal in at least saidfront and rear faces of said package each comprising one thickness ofsaid flexible packaging material secured to at least one discrete stripof substantially constant thickness flexible material, consisting of thesteps of, a) transporting in lengthwise direction a web of flexiblepackaging material of selected width and indeterminate length having atleast one thermoformable strip of a length substantially greater thanthe strip width affixed to the web with the strip length orientedtransversely to the running length of the film at package lengthintervals, b) passing said film over a forming collar and around acylindrical forming tube and forming a longitudinally sealed cylindricaltube of packaging film with the said at least one thermoformable stripinside the film tube, and with the surface of the said at least onestrip not secured to the film being in facing relationship within thetube, c) moving the film tube past a gusseting tool to provide a pair ofopposite side gussets in the tube, d) moving the portion of thegussetted tube within which the strip is disposed between a pair ofspaced apart heated male and female forming dies, e) moving said diestoward one another to press the face of the said at least one strip notsecured to the film against itself to form two apposed strip facesextending at least partly across the film tube, and continuing to movesaid dies toward one another into mating position and forming thecentral part of the strip extending across the film tube into the recessof said female die to form the tip of an arrowhead shape of thereclosable seal, f) moving toward one another into closed position apair of interlock forming heated dies positioned at opposite sides ofthe female die to press portions of the margins of the strip immediatelyadjacent to the central part of the strip inward against one another tocomplete the inner male and outer female parts of the reclosableinterlocking seal held between the female die and the pair of interlockforming heated dies while partially retracting the male die, and g)fully retracting the male and female dies to their initial positions.33. The method of making a resealable package having a reclosableinterlocking seal as set forth in claim 32 wherein said step of pressingportions of the margins of the strip immediately adjacent to the centralpart of the strip inward against one another to form the inner and outerparts of the reclosable interlocking seal includes, the step of movingsaid interlock forming dies inward to pinch together the portion of thestrip therebetween to form the inturned base of the arrowhead shape inthe interfitted parts of the reclosable interlocking seal, and thefurther step of forming detents in portions of the margins of the stripnext remote from the inturned base of the arrowhead shape of thereclosable seal.
 34. The method of making a resealable package having areclosable interlocking seal as set forth in claim 32 wherein the stepof completing the reclosable interlocking seal and partially retractingthe male die includes the sequential steps of, a) partially closing theinterlock forming heated dies to begin formation of the inwardly slopingbottom surfaces of the arrowhead shaped interlock seal but not closedsufficiently to clamp the male die, b) partially withdrawing the maledie so that it is out from between the interlock forming heated dies, c)completely closing the interlock forming heated dies to continueformation of the inwardly sloping bottom surfaces of the arrowheadshaped interlock seal and forming snap detents in portions of themargins of the strip next remote from the inturned base of the arrowheadshape of the reclosable seal, and d) moving the female die toward themale die to set the arrowhead shape of the interlock seal between thefemale die and the interlock forming heated dies.
 35. The method ofmaking a resealable package having a reclosable interlocking seal as setforth in claim 32 including the further steps of, a) heat sealing thepackage completely transversely across its width above the reclosableseal, b) cutting through the heat seal transversely to the package widthto form a package top heat seal and a bottom heat seal for the nextpackage to be formed, and wherein when the male and female dies arefully retracted to their initial positions, the interlock forming diesremain in their closed position so that the package is carried laterallyoutward with the female die away from the male die, the dies retractionfollowing the heat sealing and cutting steps.
 36. Apparatus for making agussetted package having a reclosable interlocking seal includinginterfitting male and female parts and snap detents, and end seals atopposite ends of the package, comprising in combination, a) means fortransporting in lengthwise direction a web of flexible packagingmaterial of selected width and indeterminate length havingthermoformable strips of a length substantially greater than the stripswidth, said strips being affixed to the web with the strips lengthsoriented transversely to the running length of the film at packagelength intervals, b) a pair of spaced apart heated male and female diesfor partly forming the inner and outer separable portions of thereclosable interlocking seal with the inner portion fitted within theouter portion, c) a forming collar and means for moving the film oversaid forming collar and around a cylindrical forming tube and forming alongitudinally sealed cylindrical tube of packaging film with thethermoformable strips inside the film tube and with the surfaces of thestrips not secured to the film being in facing relationship within thetube, d) gusset forming tooling for forming a pair of opposite sidegussets in said cylindrical tube, said film moving means being effectiveto move the portion of the gussetted tube within which the strips aredisposed into position between said pair of spaced apart heated male andfemale dies, e) male and female dies moving means effective whenactuated in a first way for moving said male and female dies toward oneanother to press the faces of the strips not secured to the film againstone another to form two apposed strips faces extending at least partlyacross the film tube, and effective for continuing to move said diestoward one another into mating position and forming the central part ofthe strips extending across the film tube into the recess of said femaledie to form the tip of an arrowhead shape of the reclosable interlockingseal, said male and female dies moving means when actuated in a secondway being effective to partially retract said male die, and beingeffective when actuated in a third way to fully retract said male andfemale dies to their initial positions, f) a pair of spaced apartinterlocking seal completing heated dies disposed at opposite sides ofsaid female die and having open and closed positions, said interlockingseal completing dies being effective when closed to press portions ofthe margins of the strips immediately adjacent to the central part ofthe strip inward against one another to form the inturned base of thearrowhead shape in the inner and outer portions of the reclosableinterlocking seal and hold the seal within the female die, and saidinterlocking seal completing dies being effective when opened to releasethe formed seal from the said female die, and g) operating meansactuatable for moving said interlocking seal completing heated diesbetween said open and closed positions.
 37. Apparatus as set forth inclaim 36 wherein when said male and female dies are being retracted totheir initial positions, said interlock seal completing dies remain intheir closed position so that the package reclosable seal is held withinsaid female die and the package is carried laterally outward with saidretracting female die, said interlocking seal completing dies operatingmeans being actuatable to open said dies after said female die has beenfully retracted.
 38. Apparatus as set forth in claim 36 furtherincluding package sealing and severing means for sealing and severingfrom one another adjacent ends of successive packages, said operatingmeans for opening said interlock completing dies being actuated afterthe heat sealed adjacent ends of successive packages have been severedand said female die has been fully retracted.
 39. Apparatus as set forthin claim 36 wherein said pair of spaced apart interlock completingheated dies disposed in open position at opposite sides of the femaledie are operative when closed to press portions of the margins of thestrip immediately adjacent to the central part of the strip inwardagainst one another to form the inturned base of the arrowhead shape inthe inner and outer portions of the reclosable interlocking seal heldwithin the female die, and are operative to form detents in a majorlength of the portions of the margins of the strip next remote from theinturned base of the arrowhead shape of the reclosable seal, saidinterlock completing dies having rows of apposed spaced teeth which whenbrought together force thermoformable strip material outward between theteeth to form said detents, said apposed spaced teeth extendingcentrally along the length of the interlock completing dies with theterminal portions of the dies being flat, untoothed, and of slightlyreduced elevation in the regions of the gussets.
 40. Apparatus formaking a reclosable interlocking seal having a female outer part, a maleinner part and snap detents, for a resealable gussetted package havingfront and back faces and at least one side gusset, the package beingformed from a longitudinally sealed gussetted cylindrical tube ofpackaging film with at least one thermoformable strip secured to thefilm inside the tube and with the surface of said at least one strip notsecured to the film in facing relationship within the tube, comprising,a) a pair of spaced apart heated male and female dies, b) means formoving the portion of the gussetted tube within which said at least onestrip is disposed between said pair of spaced apart heated male andfemale dies, c) means effective when actuated in a first way for movingsaid male and female dies toward one another to press the faces of thestrips not secured to the film against one another to form apposed stripfaces extending at least partly across the gussetted film tube, andeffective for continuing to move said dies toward one another intomating position to form the central part of the strip extending acrossthe film tube into the recess of said female die to form the tip of anarrowhead shaped reclosable seal in the front and back faces and theincluded gussets, said means for moving said male and female dies towardone another also being operative when actuated in a second way to movesaid male and female dies away from one another, d) a pair of interlockseal completing and detent forming heated dies positioned at oppositesides of the female die and having open and closed positions which whenin closed position are operative to press portions of the margins of thestrip immediately adjacent to the central part of the strip inwardagainst one another to form the inturned base of the arrowhead shape inthe inner and outer portions of the reclosable interlocking seal heldwithin the female die, and operative to form detents in at least aportion of the margins of the strip next remote from the inturned baseof the arrowhead shaped reclosable seal, e) means for moving toward oneanother into closed position said pair of interlock seal completingheated dies positioned at opposite sides of said female die effective tocomplete the inner male and outer female parts and snap detents of thereclosable interlocking seal held between said female die and said pairof interlock seal completing heated dies.
 41. Apparatus for making areclosable interlocking seal as set forth in claim 40 wherein saidinterlock seal completing dies have rows of apposed spaced teeth whichwhen brought together force thermoformable strip material outwardbetween the teeth to form said detents, said apposed spaced teethextending centrally along the length of the interlock completing dieswith the terminal portions of the dies being flat, untoothed, and ofslightly reduced elevation in the regions of the gussets.